Extreme pressure lubricant



United States Patent 3,239,464 EXTREME PRESSURE LUBRICANT Howard J.Matson, Harvey, and John W. Nelson, Lansing, 111., assignors to SinclairResearch, Inc., New York, N.Y., a corporation of Delaware No Drawing.Filed Sept. 5, 1961, Ser. No. 135,802 4 Claims. (Cl. 252--46.6)

The present invention relates to novel compounds having particularutility as extreme pressure and antiwear agents in oleaginous baselubricants.

Mineral oil and synethetic lubricants, in the form of greases o-rfree-flowing liquids, are called upon to ease friction and preventdamage to machinery operated at temperatures to as high as about 450 F.At elevated temperatures an internal combustion engine using theselubricants is an ideal oxidizing machine since the lubricant isviolently agitated in the presence of air for long periods of time. Inaddition the stability of the lubricants is 'further drastically reduceddue to contact with metallic surfaces which give up metallic particlesto the lubricant that act as powerful oxidation catalysts. Furthermore,water also causes corrosion of metallic surfaces and accentuatesoxidation of the lubricant. Aside from being stable under conditions ofuse the lubricant must exhibit antiwear and load-carrying or extremepressure characteristics.

It has now been discovered that the novel compounds of the presentinvention When added in small effective amounts to oleaginous baselubricating oils provide a lubricant composition with improved antiwearand extreme pressure characteristics. Many of the novel compounds, inaddition, endow lubricants with improved oxi dation resistance. Thenovel compounds of the present invention can be represented by thefollowing general formula:

2 Yn Y, z

wherein P is phosphorus; O is oxygen; D is a divalent aliphatichydrocarbon radical of 1 to 5 carbon atoms and 0:0 to 1; Z is a radicalselected from the group consisting of in which R is selected from thegroup consisting of hydrogen and an alkyl radical of 1 to 20 carbonatoms. I

is a cyclic radical selected from the group consisting of phenyl andcyclohexyl; Y is a Group VIA atom of up to 52 atomic number, such asoxygen, selenium, tellurium and sulfur; and n is 0 to 1. At least one ofthe Z radicals on each phosphorus atom should contain an R group to givesolubility to the compound and preferably the R group will average 5 ormore carbon atoms. When both sulfur and oxygen are present in thecompound it is preferred that the R group average 12 or more carbonatoms.

In general the novel compounds of the present invention are thecondensation products of bisphenol or hisphenol or hydrogenatedbisphenol, the particular phospane or the corresponding cyclohexylcompounds such as 2,2-bis(4-hydroxycyclohexyl) propane with (I) amonophenol or thiophenol and a phosphorous halide; or

(II) a phenyl phosphorous halide; or

(III) a phenyl phosphorus halide and a monophenol or thiophenol.

Thus, depending upon Whether the reactants of I, II or III are selectedfor condensation with the particular bisp henol or hydrogenatedbisphenol, the particular phosphorous halide or benzene phosphorouschloride employed, the compounds of the present invention can bediphosphites, diphosphates, dithiophosphates, diphosphonites,diphosphonates, dithiophosphonates, disphosphinates, disphosphinates ordithiophosphinates.

The cyclic radicals can be substituted, if desired, with non-interferinggroups and it is preferred that they be halogenated for instance, withfrom 1 to 4 halogens of atomic number of 17 to 35, such as chlorine,bromine or iodine. Particularly preferred bisphenols are thebis(3,5-dichloro) compounds such as 2,2-bis(3,5-dichloro-4hydroxyphenyl)propane.

The monophenol and/or thiophenol reactants of the present invention canhe alkylated as with an alkyl group of 1 to 20 carbon atoms, preferably4 to 12 carbon atoms; the alkyl group being preferably located in a paraposition to the 41-1 or OH group. Particularly suitable alkylatedphenols and thiophenols are, for example, cresol-s, para tertiary butylphenol, para tertiary octylphenol, para tertiary butyl thiophenol,thioxylenol and the like.

Examples of appropriate phosphorous halides are phosphorous trichloride,phosphorous, oxychloride, thiophosphoryl chloride. Suitable phenylphosphorous halides are, for instance, phenyl phosphoric dichloride,phenyl phosphorous thiodichloride, preferably wherein the phenyl groupis alkylated as with alkyl groups of 1 to 20 carbon atoms, preferably 4to 12 carbon atoms.

The compounds of the present invention can be conveniently prepared in ahydrocarbon solvent, for instance toluene, xylene, etc. at atmosphericpressure at temperatures of from about to 250 0., generally from about100 to C., using an amine such as pyridine, triethylamine, etc. as ahydrogen halide acceptor. The diphosphates and diphosphites can beprepared, for instance, by first slowly adding 2 moles of a monophenolor thiophenol to 1 mole of the appropriate phosphorus halide, forexample, PCl or POCl to replace two of the halide atoms. Two of theresulting monohalide molecules are then coupled with the his hydroxyreactant such as 2,2-bis(4- hydroxyphenyl) propane or2,2-bis(4-hydroxycyclohexyl) propane. The diphosphonites anddiphosphonates can be prepared respectively by reacting equimolecularproportions of a benzene phosphonohalide or a benzene phosphinous halideand the monophenol or thiophenol and then reacting the resulting productwith the bis compound reactant in a molar ratio of about 2:1. Thediphosphinites and diphosphinates can be prepared, for instance, byreacting directly in equimolar proportions a dibenzylphos phonohalide ora dibendylphosphinous halide and the his compound reactant. Thedithiophosphates, dithiophosphonates and dithiophosphinates of thepresent invention can be prepared by employing the appropriatephosphorous thiohalide or alternatively by sulfurizing, as with flowersof sulfur, the diphosphite, diphosphonite or diphosphinite compounds.

The lubricating oil base stock used in the present invention is oflubricating viscosity and can be, for instance, a solvent extracted orsolvent refined oil obtained in accordance with conventional methods ofsolvent refining lubricating oils. Generally, lubricating oils haveviscosities from about 20 to 250 SUS at 210 F. The base oil may bederived from paraflinic, naphthenic, asphaltic or mixed base crudes, andif desired, a blend of solvent- .treated Mid-Continent neutrals andMid-Continent bright 250 SUS at 210 F. and preferably 30 to 150 SUS at210 F. These esters are of improved thermal stability, low acid numberand high flash and fire points. The complex esters, diesters, monoestersand polyesters may be used alone or to achieve the most desirableviscosity. characteristics, complex esters, diesters and polyesters maybe blended with each other or with naturally-occuring esters like castoroil to produce lubricating compositions of wide viscosity ranges whichcan be tailor-made to meet various specifications. This blending isperformed,

for example, by stirring together a quantity of diester and complexester at an elevated temperature, altering the proportions of eachcomponent until the desired viscosity is reached.

These esters are prepared fundamentally by the action of acids onalcohols. The mere mixture of an alcohol and acid at the propertemperature will react to produce an equilibrium mixture which includesthe monoester. The same is true for the reactions of organic dibasicacids and glycols to produce synthetic lubricant polyester :brightstock. The diesters are frequently of the type alcohol-dicarboxylicacid-alcohol, while complex esters are generally of the type XYZYX inwhich X represents a monoalcohol residue, Y represents a dicarboxylicacid residue and Z represents a glycol residue and the linkages areester linkages. These esters have been found to be especially adaptableto the conditions to which turbine engines are exposed, since they canbe formulated to give a desirable combination of high flash point, lowpour point, and high viscosity at elevated temperature, and need containno additives which might leave a residue upon volatilization. Inaddition, many complex-esters have shown good stability to shear.Greases which use these esters as the oleaginous base also have most ofthese characteristics.

Suitable monoand dicarboxylic acids used to make synthetic esterlubricant bases can be branched or straight chain and saturated orunsaturated and they frequently contain from about 2 to 12 carbon atoms.The alcohols usually contain from about 4 to 12 carbon atoms. Ingeneral, the useful glycols include the aliphatic monoglycols of 4 to 20or 30 carbon atoms, preferably 4 to 12.

The compositions of this invention incorporate a small,

.minor amount of the above described additives suflicient to provide thebase oil of lubricating viscosity which is the major portion of thecomposition with improved antiwear and extreme pressure properties. Thisamount is generally about 0.01 to 15 or 20% or more depending on theparticular base oil used and its application. The preferredconcentration should be the minimum amount to give the desiredproperties for the particular application and usually will be about 0.2.to 5%. In some cases where oil solubility might limit the .amount ofadditive employed, dispersants may be used to increase theconcentration. In these cases, it has been found'thatincreasedsolubility is best obtained in highly refined oils bydissolving'the dispersant in the. oil before dissolving the additive.

Materials normally incorporated in lubricating oils and greases toimpart special characteristics can be added to the composition of thisinvention. These include corrosion inhibitors, additional extremepressure agents, anti- Wear agents, etc. The amount of additivesincluded in the composition usually ranges from about 0.01 weightpercent up to about 20 or more weight percent, and in general they canbe employed in any amounts desired as long as the composition is notunduly deleter-iously affected.

The following examples are included to illustrate .the preparation ofthe condensation products of the present invention but are not to beconsidered limiting. Any method apparent to one skilledin the art can beemployed in preparing the, compounds,

EXAMPLE I 2,2-bis[3,5-dichloro-4-(di para tertiary octylphenyl phosphitephenyl] propane A'flask was flushedwith nitrogen to remove the air and anitrogen blanket was employed to prevent hydrolysis of the =PCl and/orPH formation, during the monophenol addition. To 257 g. (3.25 moles) ofpyridine and 137 g. (1 mole) of PCl in 800 g. toluene, while stirringvigorously, were slowly added, over about one hour, 412 g. (2 moles)para-tertiary octylphenol dissolved in 600 g. toluene. The temperaturerose from 28 C. to 53 C. during the addition. Heat was then applied tothe flask via a heating mantle, the nitrogen turned off and a refluxcondenser was attached, which was protected from the air with a dryingtube. After about one-half hour 200 g. toluene were added and fifteenminutes later the toluene started to reflux at a pot temperature, of'113 C. The mixture was stirred at reflux for 6 hours and then allowed tostand and cool overnight. The next morning 183 g. 0.5 mole)2,2-bis(3,S-dichloro-4-hydroxyphenyl) propane dissolved in 1000 g.toluenev was added and the flask contents stirredand heated to refluxtemperature of 112 C. It was maintained at 112 C. for 7 hours and thenallowed to stand and cool overnight. The next day the pyridinehydrochloride was filtered off and washed with toluene. The filtrate waswas-hedwith water, dilute NaHCO and then twice Withwater again. Methanolwas used to break'the emulsions formd.. Finally it was allowed to dryover anhydrous calcium sulfate over the weekend. The mixture was thenfiltered and the filtrate topped to 226 C. at 10 mm. pressure. Thebottoms product weighed 575 g. (92.5% theory) andwas an off- White softsolid. It analyzed 4.24% phosphorus and 10.5% chlorine.

EXAMPLE II 2,2-bis[3,5-dichl0r0 4-(di para tertiary octylphenylIhiophosphate) phenyl] propane 4.07% phosphorus, 6.21% sulfur and"9.93%chlorine.

5 EXAMPLE 111 2,2-bis[4-(di para tertiary octylphenyl phosphite)cyclohexyl] propane This compound was made in a similar manner asExample I. The para tertiary octylphenol in toluene was added to P01 inpyridine and toluene over 50 minutes while the reaction temperature rosefrom 28 C. to 66 C. It was heated and stirred for 6.5 hours at 114 C.2,2-bis (4-hydroxycyclohexyl) propane partially dissolved in ether wasadded at 28 C. The ether was removed by dis-tillation, toluene added andthe mixture stirred at 112 C. for 4.5 hours. After filtering off thepyridine hydrochloride at room temperature, the filtrate was washed 3times with water using methanol to break the emulsion. After drying, themixture was topped to 203 C. at 4 mm. An appreciable amount of unreaotedpara tertiary octylphenol was removed during topping. The pale yellowplastic product, obtained in 82.5% yield, analyzed 5.65% phosphorus andacid number 2.0.

EXAMPLE IV 2,2-bis[4-(di para tertiary octy'lphenylthiophosphate)cyclhexyl]pr0pane The diphosphite of Example III was sulfurized for 24hours at 125 C. After drying the mixture was topped to 180 C. at 5 mm.'The product analyzed 5.39% phosphorus and 3.65% sulfur.

EXAMPLE V 2,Z-bis[4-(di para tertiary octylphenyl phosphate)cycl0hexyl1propane This compound was made similar to Examples I and III.Two moles of para tertiary octylphenol in 600 g. of toluene were addedto one mol of phosphorus oxychloride in 3.25 moles of pyridine and 500g. toluene over one hour. After stirring at 114 C. for 8 hours andcooling to room temperature, 0.5 mole of 2,2-bis (4-hyd roxycyclo hexyl)propane, slurred in 1000 g. ether and 300 g. acetone, and about one gramof anhydrous MgCl were added. After removing the ether and acetone bydistillation, the mixture was stirred at 113-115 C. for 4 /2 hoursduring which time about one gram each of anhydrous MgCl and AlCl wereadded. The filtered mass was washed with water and dilute NaHCO followedby 3 water-methanol washes and dried. It was topped to 200 C. at 4 mm.The yield was 63.3% theory. The product analyzed 7.0% phosphorus and0.0% chlorine.

EXAMPLE VI 2,2-bis[3,5-dichl0ro-4 (di para tertiary octylphenylphosphate phenyl] propane Percent P Percent Cl low 6 EXAMPLE v112,2-bis[3,5-dichl0r0-4-(para tertiary octylphenyl benzene-phosphanate)phenyl] propane The flask was flushed with nitrogen to remove the air.The N was continued into the flask. Eighty grams of pyridine and 390 g.(2 moles) phenylphosphonic dichloride weighed into 400 g. xylene werecharged at room temperature. Stirring was started and heat was appliedto the fiask. Over the next 40 minutes 412 g. (2 moles) para tertiaryoctyl phenol dissolved in 500 g. xylene was added dropwise or in a smallstream. The N inflow was discontinued, the flask stopped at that neckand the heat was turned up. Forty-five minutes later at 144 C. thexylene started refluxing. Then 250 g. xylene were added for bettermixing and the reaction allowed to continue for 4 hours and 10 minutesbefore being shut down for the night. The next morning the stirrer andheat were turned on. After 25 minutes and at a flask temperature of 35C., 166 g. pyridine, 366 g. (1 mole) tetrachlorobis-phenol A dissolvedin 1000 g. xylene at 75 C. and 1 g. anhydrous AlCl were added. After onehour refluxing started at 140 C. After about 1 /2 hours the materialturned green and l g. AlCl was added. After 1% hours later another gramof AlCl was added. It was then allowed to react for about 3 /2 hoursbefore being shut down for the night. The next day the pyridinehydrochloride was filtered oif using a Buechner funnel and vacuum. Thefiltrate was washed with water,

and NaHCO solution until basic. An additional H O wash turned it acidagain. It was then stirred with Dricrite and solid NaI-ICO for 1 hourand after adding Attapulgas fines, 30 minutes longer. It filtered clearand was still green. It was then evaporated down on a steam bathovernight. The next morning a precipitate was visible and it Wasfiltered again. A portion (500 g.) was again evaporated down to 365 g.but no more precipitation occurred. The mass was then topped to 225 C.at 7 mm. A green product was obtained in a yield of 86% of theory, whichanalyzed 5.79% phosphorus, 13.3% chlorine and Acid No. 44.9.

EXAMPLE VIII 2,2-bis[3,5-dichl0r0-4-(para tertiaryoctylphenylbenzene-thiophosphonate phenyl] propane This compound wasprepared in essentially the same manner as in Example VII above. Bothwere one mole runs. Three weights differed in that an extra g. pyridinewas used at the start of the reaction and 412 g. (2 moles)phenyl-phosphorous thiodichloride were weighed into 600 g. xylene,instead of 390 g. (2 moles) phenylphosphonic dichloride into 400 g.xylene, with 250 g. added after the octyl phenol.

The filtrate was not washed with NaHCO solution after water and H OMeOHwashing. It was dried the same way. No precipitate occurred on steambath removal of the toluene. A black product was obtained in yield(theory) and analyzed 5.98% phosphorus, 12.3% chlorine, 6.25% sulfur andAcid No. 44.9.

EXAMPLE IX 2,2-bis[3,5-dichl0r0-4-(di para tertiarybutylphenyl-phosphate) phenyl] propane This compound was prepared in thesame manner as the compound of Example V except that butyl phenol wasemployed instead of octyl phenol. The product was a dark green solid andanalyzed 5.81% phosphorus, 12.0% chlorine and Acid No. 59.9.

To demonstrate the advantages of the compounds of the present inventionin lubricant compositions, 1% of some of the compounds of Examples I toIX were in corporated in an oil blend (identified in Table I below) andthe lubricant compositions were subjected to an oxidation test and theShell 4-Ball Extreme Pressure and Wear Tests. The oxidation testcomprised charging 350 cc. of the oil to a large tube maintained at 285F. in an oil bath for 144 hours While introducing 5 liters of oxygen perhour at the bottom of the tube in the presence of a copper on leadcoupon measuring 1" x 3". For com- 5 R parison, the base 011 (identifiedin Table I) wlthout the additives of the present invention was alsotested. The results of the tests are shown 111 Table I. in which R -1sselected .from the group consisting of TABLE I Oil Blend Oxidation TestCompound Percent Percent Catalyst Cone. KV/100 KV/100 Vis. Rise Wt.Change Acid N 0.

Base Oil 1 28.03 38. 60 38 -20. 3 10. 6 2,2-bis[3.5-dichloro-4-(di paratertiary octylphenyl phos hite) phenyl] propane (Ex. I) 1.0 28. 74 26.208 +18. 0 2.9 2,2-bis 3,5-dichloro-4-(di para tertiary octylphenyl thiohosphate) phenyl] propane (Ex. II) 1.0 28. 46 27.18 5 +8.8 2. 7 2,2bis i4-(di para tertiary octylphenyl phosphite) cyclohexyl] propane (Ex. III)1.0 28. 89 24. 2 -16 +21. 0 2. 6 2,2-bis[4-(di ara tertiary octylphenylthiophosphate) cyelohexyl propane (Ex. IV) 1. 0 27. 17 25. 9 5 +18. 5 2.1 2,2-bis[4-(di para tertiary octylphenyl phosphate)eyclohexyl] propane(Ex. V) 1. 0 29. 75 26.3 -11 363 2. 2 2,2-bis[3,5-diohloro-4-(di paratertiary octylphenyl phos hate) phenyl] propane (Ex. VI(a)) 1.0 30. 4728.82 5 262. 1 2.9 2,2-bis 3,5-diehloro-4-(para tertiaryoctylphenyl-benzenephosphonate) phenyl] propane (Ex. VII) 1.0 28.1834.16 21 -5 6. 8 2,2-bis[3,5-dichloro-4-(para tertiaryoctylphenyl-benzene-thiophosphonate) phenyl] propane (Ex. VIII)" 1.0 27.69 234. l 745 5. 3 8. 5 2,2-bis[3,5-dichloro-4-(di para tertiarybutyl-phenyl- 7 phosphate) phenyl] propane (Ex. IX) 1. 0 28. 44 32. 59106 6.0

Oxidation Test (continued) Shell 4-Ball Compound Pentane Condition MeanAve. Insol., Initial Hertz Weld; Wear Percent pH Load kg. Diam.,

Copper Tube mm.

Base Oil 4.24 2.4 Blotchei. Lt. s1udges 13.1 141 0.552,2bis[3,5-dichloro-4-(di para tertiary octylphenyl 0. 00 2.3 CleanClean 33.6 141 0.30

phosphite) phenyl] propane (Ex. I). 2,2-bis[3,5-diehloro-4-(di paratertiary octylphenyl 0.02 2.5 Black do 26.1 141 0.30

thiophosphate phenyl] propane (Ex. II). 2,2-bis[4-di para tertiaryoetylphenyl phosphite cy- 0.00 2.4 Clean do 32 141 0.29

clohexyl] propane (Ex. III). I 2,2-bis[4-(di para tertiary octylphenylthiophosphate) 0. 01 2. 4 do do 21. 2 141 0.31

eyelohexyl] propane (Ex. IV). 2,2 bis[4-(di para tertiary octyphenylphosphate) ey- 0.01 2. 3 do do 32. 6 158 0.20

clohexyl] propane (Ex. V). 2,2-bis[3,5-dichloro-4-(di para tertiaryootylphenyl 0.02 3.1 do d0 26.3 141- 0.30

phosphate) phenyl] propane (Ex. VI(a)). 2,2-bis[3,5-diehloro-4-(paratertiary octylphenyl-ben- 1.88 1.7 Br0nze do 24.8 141 0.49

zene-phosphonate) phenyl] propane (Ex. VII).2,2-bis[3,5-diehloro-4-(para tertiary octylphenyl-ben- 3. 94 1.4 'BlackHeavy 25.6 126. 0.35

zene-thiophosphonate)phenyl]propane (Ex. VIII). sludge2,2-bis[3,5-dichloro-4-(di para tertiary butyLphenyl- 0.17 1.7 DarkClean 31.3 141 0.28

phosphate) phenyl] propane (Ex. IX).

1 Base oil is a blend of 70% of a naphthenic base raw lube distillatehaving a viscosity of to at 100 F. and 30% of a solvent refinedMid-Continent neutral oil having a viscosity of 600 SUS at 100 F. towhich has been added 3% of an ashless detergent consisting of acopolymer of 95 parts lauryl methacrylate and 5 parts dunethylaminoethyl methaerylate.

wherein P is phosphorous; O is oxygen; D is a divalent hydrocarbonradical of 1 to 5 carbon atoms and c is.0 to 1; Z is a radical selectedfrom the group consisting of:

hydrogen and alkyl-radical of 1 to 20 carbon atoms;v and is a .cyclicradical selected from the group;consisting of phenyl and cyclohexyl;about 0.01 to 20% by Weight.

2. The composition of claim 1 wherein Z is the radical:

in which R is;an alkyl radical of '1 to 20carb0n atoms. 3. An oleaginouslubricant composition consisting essentially of a base oil oflubricating viscosity and an amount sufficierrt to give improvedextremepressu-re properties to the composition of an oil-solublecompound represented by the general formula: a

said amount is being V V S wherein P is phosphorus; O is oxygen; D is adivalent hydrocarbon radical of -1 to 5 carbon atoms and c is to 1; Z isa radical selected from the group consisting of:

in which R is selected from the group consisting of hydrogen and analkyl radical of 1 to 20 carbon atoms; and

is a cyclic radical selected from the group consisting of phenyl andcyclohexyl; said amount being about 0.01 to 20% by weight.

4. An oleaginous lubricant composition consisting essentially of a baseoil of lubricating viscosity and an amount sufficient to give improvedextreme pressure properties to the composition of an oil-solublecompound represented by the general formula:

wherein P is phosphorous; O is oxygen; D is a divalent hydrocarbonradical of 1 to 5 carbon atoms and c is 0 to 1; Z is a radical selectedfrom the group consisting of:

in which R is selected from the group consisting of hydrogen and analkyl radical of l to 20 carbon atoms;

is a cyclic radical selected from the group consisting of phenyl andcyclohexyl; X is a halogen atom of atomic number 17 to 52 and n is aninteger of 1 to 4; Y is a Group VIA atom of up to 52 atomic number an nis 0 to 1, said amount being about 0.01 to 20% by weight.

References Cited by the Examiner UNITED STATES PATENTS DANIEL E. WYMAN,Primary Examiner.

JULIUS GREENWALD, Examiner.

1. AN OLEAGINOUS LUBRICANT COMPOSITION CONSISTING ESSENTIALLY OF A BASEOIL OF LUBRICATING VISCOISTY AND AND AN AMOUNT SUFFICIENT TO GIVEIMPROVED EXTREME PRESSURE PROPERTIES TO THE COMPOSITION OF ANOIL-SOLUBLE COMPOUND RESPRESENTED BY THE GENERAL FORMULA: